U.S. patent application number 15/124271 was filed with the patent office on 2017-02-16 for heat store.
This patent application is currently assigned to Siemens Aktiengesellschaft. The applicant listed for this patent is Siemens Aktiengesellschaft. Invention is credited to Vladimir Danov, Theodoros Papadopoulos.
Application Number | 20170045303 15/124271 |
Document ID | / |
Family ID | 53175424 |
Filed Date | 2017-02-16 |
United States Patent
Application |
20170045303 |
Kind Code |
A1 |
Danov; Vladimir ; et
al. |
February 16, 2017 |
Heat Store
Abstract
A heat accumulator for storing thermal energy may include a
container with a horizontally-extending longitudinal axis, and a
heat storage material in the form of a plurality of stone-like
elements contained in the container. The container may include a
first opening formed at a first portion of the container, and a
second opening formed at a second portion of the container, the
second opening being vertically offset with respect to the first
opening. An average diameter of the stone-like elements arranged in
the first portion of the container may be larger than an average
diameter of the stone-like elements arranged in the second portion
of the container.
Inventors: |
Danov; Vladimir; (Erlangen,
DE) ; Papadopoulos; Theodoros; (Muenchen,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Siemens Aktiengesellschaft |
Muenchen |
|
DE |
|
|
Assignee: |
Siemens Aktiengesellschaft
Muenchen
DE
|
Family ID: |
53175424 |
Appl. No.: |
15/124271 |
Filed: |
April 23, 2015 |
PCT Filed: |
April 23, 2015 |
PCT NO: |
PCT/EP2015/058785 |
371 Date: |
September 7, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F28D 20/0056 20130101;
F28F 21/04 20130101; Y02E 60/14 20130101; Y02E 60/142 20130101;
F28D 2020/0086 20130101; F28D 2020/0069 20130101; F28F 2270/00
20130101 |
International
Class: |
F28D 20/00 20060101
F28D020/00; F28F 21/04 20060101 F28F021/04 |
Foreign Application Data
Date |
Code |
Application Number |
May 6, 2014 |
DE |
10 2014 208 454.7 |
Claims
1. A heat store for storing thermal energy, the heat store
comprising: a container with a horizontally extending longitudinal
axis, the container comprising: a heat store material comprising a
plurality of stone-like elements, a first partial region of the
container in which a first portion of the stone-like elements are
arranged, the first partial region having a first opening, and a
second partial region of the container in which a second portion of
the stone-like elements are arranged, the second partial region
having a second opening that is offset vertically with respect to
the first opening, wherein a mean diameter of the stone-like
elements arranged in the first partial region is greater than a
mean diameter of the stone-like elements arranged in the second
partial region.
2. The heat store of claim 1, wherein the stone-like elements
comprise at least one of stones, bricks, or a ceramic material.
3. The heat store of claim 1, wherein a vertical extent of the heat
store perpendicular to the longitudinal axis is at most 10 m.
4. The heat store of claim 1, comprising at least one
fluid-permeable distributor plate arranged between the stone-like
elements arranged in the first partial region and the stone-like
elements arranged in the second partial region.
5. The heat store of claim 4, wherein the at least one distributor
plate comprises a heat-resistant steel.
6. The heat store of claim 4, wherein the at least one distributor
plate comprises a nonwoven material.
7. The heat store of claim 4, wherein the at least one distributor
plate comprises a wire grid.
8. The heat store of claim 1, wherein the first opening is located
at a first side of the container and the second opening is located
at a second side of the container opposite the first side.
9. The heat store of claim 1, comprising a third opening arranged
in the first partial region of the container and a fourth opening
arranged in the second partial region of the container.
10. The heat store of claim 8, wherein the first opening and the
fourth opening are located at a first side of the container, and
the second opening and third opening are located at a second side
of the container.
11. A method, comprising: providing a heat store including a
container having a heat store material comprising a plurality of
stone-like elements, with a first portion of the stone-like
elements are arranged in a first partial region of the container
having a first opening and a second portion of the stone-like
elements arranged in a second partial region of the container
having a second opening offset vertically from the first opening,
wherein a mean diameter of the stone-like elements arranged in the
first partial region is greater than a mean diameter of the
stone-like elements arranged in the second partial region;
delivering a fluid into the container of the heat store via the
first opening or second opening and bringing the fluid into thermal
contact with the heat store material; and at least one of:
discharging the heat store by causing the fluid to flow in through
the first opening and out through the second opening; or charging
the heat store by causing the fluid to flow in through the second
opening and flow out through the first opening.
12. The method of claim 11, wherein: the heat store further
comprises a third opening arranged in the first partial region of
the container and a fourth opening arranged in the second partial
region of the container, and the heat store is discharged by
additionally causing the fluid to flow in through the third opening
and flow out through the fourth opening.
13. The method of claim 11, wherein: the heat store further
comprises a third opening arranged in the first partial region of
the container and a fourth opening arranged in the second partial
region of the container, and the heat store is charged by
additionally causing the fluid to flow in through the fourth
opening and flow out through the third opening.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a U.S. National Stage Application of
International Application No. PCT/EP2015/058785 filed Apr. 23,
2015, which designates the United States of America, and claims
priority to DE Application No. 10 2014 208 454.7 filed May 6, 2014,
the contents of which are hereby incorporated by reference in their
entirety.
TECHNICAL FIELD
[0002] The invention relates to a heat store or heat accumulator
for storing thermal energy.
BACKGROUND
[0003] Heat stores are thermal energy stores which store thermal
energy (heat) and thus temporally decouple the generation of
electrical energy from the generation or provision of the thermal
energy. The thermal energy stored by means of the heat store can
then be guided directly to the consumer as heat or can be used
again for generating electrical energy.
[0004] One possible heat store is a bulk material store comprising
stones or bricks as bulk material. In this case, the bulk material
store is typically charged by means of a fluid at a temperature of
approximately 600.degree. C.
[0005] The prior art distinguishes between vertically and
horizontally oriented heat stores. In particular, in contrast to a
vertical heat store, a vertical temperature front is present in a
horizontal heat store. During the charging or discharging of the
horizontal heat store, said vertical temperature fronts are
distorted on account of the natural convection which takes place in
the horizontal direction, and therefore the heat store is
non-uniformly charged or discharged with respect to the
temperature. This limits the efficiency of horizontal heat
stores.
[0006] According to the prior art, an attempt is made to hinder the
natural convection by means of horizontal and/or vertical plates
arranged within the horizontal heat store. A high number of plates
is typically required for this purpose, however. In the case of
vertically arranged plates, the pressure losses are additionally
increased when charging or discharging the horizontal heat
store.
SUMMARY
[0007] One embodiment provides a heat store for storing thermal
energy, comprising a container with a horizontally extending
longitudinal axis, wherein the container comprises a heat store
material formed from a plurality of stone-like elements, wherein
the container has a first opening in a first partial region and, in
a second partial region, a second opening offset vertically with
respect to the first opening, wherein a mean diameter of the
stone-like elements arranged in the first partial region is greater
than a mean diameter of the stone-like elements arranged in the
second partial region.
[0008] In one embodiment, the heat store material comprises stones,
bricks and/or a ceramic material.
[0009] In one embodiment, a vertical extent of the heat store
perpendicular to the longitudinal axis is at most 10 m.
[0010] In one embodiment, at least one fluid-permeable distributor
plate is arranged between the heat store material arranged in the
first partial region and the heat store material arranged in the
second partial region.
[0011] In one embodiment, the distributor plate comprises a
heat-resistant steel.
[0012] In one embodiment, the distributor plate comprises a
nonwoven material.
[0013] In one embodiment, the distributor plate comprises a wire
grid.
[0014] In one embodiment, a first side of the container has the
first opening and a second side of the container lying opposite the
first side has the second opening.
[0015] In one embodiment, the heat store includes a third and a
fourth opening, wherein the third opening is arranged in the first
partial region and the fourth opening is arranged in the second
partial region.
[0016] In one embodiment, the first side comprises the fourth
opening and the second side comprises the third opening.
[0017] Another embodiment provides a method for operating a heat
store as disclosed above, in which a fluid is made to flow into the
container of the heat store by means of the first or second opening
and is brought into thermal contact with the heat store material,
wherein the heat store is discharged by making the fluid flow in
through the first opening and flow out through the second opening
and/or the heat store is charged by making the fluid flow in
through the second opening and flow out through the first
opening.
[0018] In one embodiment of the method, the heat store is
discharged by additionally making the fluid flow in through the
third opening and flow out through the fourth opening.
[0019] In one embodiment of the method, the heat store is charged
by additionally making the fluid flow in through the fourth opening
and flow out through the third opening.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Example aspects and embodiments of the invention are
discussed below with reference to the sole drawing, FIG. 1, which
shows an example heat store comprising a horizontally extending
distributor plate arranged between a first and a second partial
region.
DETAILED DESCRIPTION
[0021] Embodiments of the invention may provide an improved
horizontal heat store.
[0022] Some embodiments provide a heat store for storing thermal
energy comprises a container with a horizontally extending
longitudinal axis, wherein the container comprises a heat store
material formed from a plurality of stone-like elements, and the
container has a first opening in a first partial region and, in a
second partial region, a second opening offset vertically with
respect to the first opening, wherein a mean diameter of the
stone-like elements arranged in the first partial region is greater
than a mean diameter of the stone-like elements arranged in the
second partial region.
[0023] A horizontally oriented, or a horizontal, heat store is
formed by the horizontally extending longitudinal axis.
[0024] By way of example, the mean diameter of the stone-like
elements is to be considered to be a diameter, averaged over the
stone-like elements, of a minimum or maximum extent of the
stone-like elements. This can also provide a greater mean aspect
ratio of the stone-like elements arranged in the first partial
region compared to the stone-like elements arranged in the second
partial region. An individual aspect ratio denotes the ratio of
maximum extent to minimum extent of a stone-like element. The mean
aspect ratio in turn denotes an average of the individual aspect
ratios.
[0025] In the first partial region of the container, the stone-like
elements arranged therein have, a greater mean diameter than the
stone-like elements arranged in the second partial region. In this
case, the second partial region of the container, which comprises
the stone-like elements with the smaller mean diameter, forms the
actual partial region of the heat store for storing the thermal
energy. In this case, the first partial region is provided for the
horizontal, uniform distribution of an inflowing or outflowing
fluid. The fluid is distributed by the enlarged stone-like elements
arranged in the first partial region, which on average have a
greater diameter than the stone-like elements arranged in the
second partial region. Advantageously, the distribution is thereby
effected with the lowest possible pressure loss. After the uniform
distribution of the fluid by means of the first partial region, the
fluid flows from the first partial region into the second partial
region. This gives rise to an approximately vertical flow
progression of the fluid, and it is therefore the case that an
approximately horizontal temperature front is established within
the heat store, or the container.
[0026] In other words, the disclosed heat store permits a
horizontal temperature front in a horizontal heat store. The
horizontal heat store consequently makes it possible to transfer
the advantage of vertical heat stores--the horizontal temperature
front--to horizontally oriented heat stores. Consequently, the
temperature front of the horizontal heat store is not distorted
during charging, discharging and/or in phases of rest by natural
convection, which now takes place in a direction perpendicular to
the horizontal temperature front (vertical direction). This
improves the efficiency of the heat store. Temperature gradients
within the heat store are reduced by the vertical offset of the
first and second openings. The vertical spacing between the first
opening and the base of the container is preferably smaller than
the vertical spacing between the second opening and the base of the
container. Furthermore, provision is made of a smaller vertical
spacing between the second opening and the cover of the container
compared to a vertical spacing between the first opening and the
cover of the container. In other words, the first opening is
arranged in the vicinity of the base of the container and the
second opening is arranged in the vicinity of the cover of the
container. As a result, the first and the second opening have the
mutual vertical offset. The temperature of a fluid flowing in or
flowing out through the first opening is expediently lower than the
temperature of a fluid flowing in or flowing out through the second
opening.
[0027] Some embodiments provide a method for operating a heat
store, wherein a fluid is made to flow into the container of the
heat store by means of the first or second opening and is brought
into thermal contact with the heat store material, wherein the heat
store is discharged by making the fluid flow in through the first
opening and flow out through the second opening and/or the heat
store is charged by making the fluid flow in through the second
opening and flow out through the first opening.
[0028] For discharging, a cold fluid is made to flow into the
container of the heat store by means of the first opening arranged
in the first partial region, and a hot fluid is made to flow out by
means of the second opening arranged in the second partial region
of the container. In this respect, the first partial region is
arranged in the vicinity of the base and the second partial region
is arranged in the vicinity of the cover of the container. The cold
fluid in this case is at a temperature which is lower than the
temperature of the heat store material. The hot fluid is at a
higher temperature than the heat store material. In other words,
during discharging, the heat stored in the heat store, or in the
heat store material, is transferred by the thermal contact from the
heat store material to the fluid. A temperature of the fluid of
approximately 453.15 K (180.degree. C.) is provided when the cold
fluid flows in and a temperature of the fluid of approximately
873.15 K (600.degree. C.) is provided when the hot fluid flows
out.
[0029] What is achieved by arranging the first opening in the
vicinity of the base and the second opening in the vicinity of the
cover is an advantageous flow progression of the fluid through the
container, this progressing from the base of the container to the
cover of the container during discharging of the heat store. In
this case, the fluid flowing in through the first opening is
distributed within the container by the first partial region in
such a manner that an approximately vertical flow progression of
the fluid within the second partial region is achieved. This
achieves an approximately homogeneous horizontal temperature
distribution, or an approximately horizontal temperature front.
[0030] During charging of the store, the fluid is made to flow in
through the second opening and flow out through the first
opening.
[0031] In addition, advantages of the method according to the
invention which are similar and equivalent to those of the
aforementioned heat store according to the invention are
achieved.
[0032] According to one embodiment, the heat store material is
formed from a plurality of stone-like elements. In this respect,
particular preference is given to a heat store material which
comprises stones, bricks and/or a ceramic material.
[0033] This is therefore advantageous since stones, bricks and/or
ceramic materials have a particularly high heat capacity, and
therefore a particularly efficient heat store is formed using the
aforementioned heat store materials.
[0034] Preference is given to a heat store having a vertical extent
perpendicular to the longitudinal axis thereof of at most 10 m.
[0035] In other words, the heat store forms a horizontal heat
store. Compared to a vertical heat store, a horizontal heat store
has the advantage that the geometrical extent along the
longitudinal axis, which in the case of the vertical store
corresponds to the height of the store, essentially is not
subjected to any limitation. In addition, horizontal heat stores
are technically less complex than vertical heat stores. In this
context, the longitudinal axis denotes that axis of the heat store
which corresponds to the direction of its greatest geometrical
extent.
[0036] According to one embodiment, at least one fluid-permeable
distributor plate is arranged between the heat store material
arranged in the first partial region and the heat store material
arranged in the second partial region.
[0037] Advantageously, the fluid which is made to flow in in the
first partial region of the container is distributed approximately
uniformly and horizontally in the heat store material by means of
the fluid-permeable distributor plate. In this respect, the fluid
is transferred from the first partial region into the second
partial region via the fluid-permeable distributor plate. This
further improves the horizontal temperature front within the
container.
[0038] Preference is given in this respect to a distributor plate
which comprises a heat-resistant steel. This expediently ensures
that the distributor plate satisfies necessary thermal requirements
which arise through the arrangement of the distributor plate within
the container. A distributor plate which comprises a nonwoven
material or mat of fibers may be advantageous.
[0039] By configuring the distributor plate as a nonwoven material
or mat of fibers, the fluid is advantageously distributed
approximately uniformly in the heat store material within the
container. A further advantage of the nonwoven material is that the
nonwoven material adapts to the shape and form of the heat store
material and consequently can follow deformation of the heat store
material, for example as a result of thermal loading. It is
therefore not necessary for the distributor plate to have a
load-bearing function. In particular, provision is made of a thin
configuration of the distributor plate.
[0040] According to one embodiment, a first side of the container
has the first opening and a second side of the container lying
opposite the first side has the second opening.
[0041] Advantageously, the fluid thereby flows through
approximately the entire heat store. This improves the efficiency
of the heat store.
[0042] According to one embodiment, the heat store comprises a
third and a fourth opening, wherein the third opening is arranged
in the first partial region and the fourth opening is arranged in
the second partial region.
[0043] In this respect, it is preferable that the third opening is
arranged on the second side of the container and the fourth opening
is arranged on the first side of the container. As a result, the
second opening and the third opening of the container are arranged
on the same side, the second side, of the container. The first and
fourth openings are arranged on the first side of the container.
This further improves the flow progression of the fluid within the
container. In particular, the third opening is used in the manner
of the first opening and the fourth opening is used in the manner
of the second opening.
[0044] In other words, the heat store is charged by making the
fluid flow in through the second and the fourth opening and flow
out through the first and third openings. The heat store is
discharged by making the fluid flow in through the first and third
openings and by making the fluid flow out through the second and
fourth openings.
[0045] FIG. 1 shows a heat store 1, which comprises a container 2
with a first opening 81, a second opening 82, a third opening 83
and a fourth opening 84. In this case, the first opening 81 and the
fourth opening 84 are provided on a first side 91 of the container
2. The second opening 82 and the third opening 83 are arranged on a
second side 92 of the container 2. The second opening 82 and the
fourth opening 84 are located in the vicinity of a cover 16 of the
container 2 with respect to a vertical direction V. As a result of
the second and fourth openings 82, 84 being arranged in the
vicinity of the cover 16, the vertical spacing between the second
and fourth openings 82, 84 and the cover 16 is smaller than the
vertical spacing between the second and fourth openings 82, 84 and
a base 14 of the container 2. By contrast, the first and third
openings 81, 83 are arranged in the vicinity of the base 14 of the
container 2.The terms "horizontal" and "vertical" always refer to a
gravitational force prevailing at the site of the heat store 1
(vertical direction).
[0046] The container 2 extends along a longitudinal axis, the
longitudinal axis running substantially parallel to a horizontal
direction H (perpendicular to the vertical direction). As a result,
the heat store 1 is in the form of a horizontal heat store 1.
[0047] The single figure shows the discharging of the heat store 1
by means of the flow directions 20, 21, 22. During discharging of
the heat store 1, the flow directions 20, 21, 22 illustrated are
reversed. However, the advantage of the improved distribution of
the fluid within the container 2 and a resultant horizontal
temperature front 24 is retained during charging.
[0048] A heat store material 5 formed from a plurality of
stone-like elements 4, in particular from stones 4, is arranged
within a first partial region 61 of the container 2. Furthermore, a
further heat store material 5 is arranged in a second partial
region 62 of the container 2. In this case, the stone-like elements
4 of the heat store material 5 in the second partial region 62 have
a smaller mean diameter than the stone-like elements 4 in the first
partial region 61. A horizontally extending distributor plate 12 is
arranged between the first partial region 61 and the second partial
region 62. In this case, the distributor plate 12 serves for a
further horizontal distribution of the fluid, such that an
approximately horizontally extending temperature front 24 is
formed.
[0049] In the illustrated case of discharging of the heat store 1,
cold fluid is made to flow into the first partial region 61 of the
container 2 by means of the first and third openings 81, 83. In
this case, the direction in which the fluid flows in is denoted by
the arrows 20 and the flow direction within the container 2 is
denoted by the arrows 22.
[0050] During discharging of the heat store 1, the cold fluid
flowing in by means of the first and third openings 81, 83 is at a
lower temperature than the heat store material 5 arranged in the
first and/or second partial region 61, 62. By virtue of the
enlarged mean diameter, of the stone-like elements 4 arranged in
the first partial region 61, the inflowing fluid is distributed
approximately uniformly horizontally over the horizontal extent of
the container 2, without excessively high pressure losses arising.
Then, the fluid flows via the distributor plate 12 into the second
partial region 62 of the container 2. In the process, the
distributor plate 12 additionally distributes the inflowing fluid
horizontally along the container 2. This results in the
approximately horizontally running temperature front 24.
[0051] What is formed overall by virtue of the mutually vertically
offset first and second openings 81, 82 and by virtue of the
different mean diameters of the stone-like elements 4 in the first
and second partial regions 61, 62 is a horizontal heat store 1,
which, like a vertical heat store, has a horizontal temperature
front 24. The disclosed heat store 1 therefore synergistically
combines the advantages of a horizontal heat store with the
advantages of a vertical heat store.
[0052] Although the invention has been described and illustrated in
more detail by the preferred exemplary embodiments, the invention
is not limited by the disclosed examples, or other variations can
be derived therefrom by a person skilled in the art without
departing from the scope of protection of the invention.
* * * * *